Method of and means for equalizing the potentials of grounding-points.



- A. B. CLARK.

METHOD OF AND MEANS FOR EQUALIZING THE POTENTIALS OF GROUNDING POINTS.

I ANPLIGATION FILED OUT. 29, 1913. Lmfi fifia Patented Feb.2,1915

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METHOD OF AND MEANS FOR EQUALIZING THE POTENTIALS OF GROUNDING POINTS.

APPLICATION FILED 00129, 1913. 1,126,956, Patented Feb.2,1915.

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fiZVlLfOZ? smash sra'rns Parana o ALVA- n. omen, or naooxmm, new YORK,ASSIGNOB. TO mnarcan 'rnnnrnonn arm TELEGRAPH company, A conrona'non ornew "roan.

Specification of Letters'l atent.

Patented Feb. 2,- 1915.

Application filed October as, 1913. Serial No. 798,087.

To all whom it may concern.

Be it known that I, ALVA B. CLARK, re-

' siding at Brooklyn, in the county of Kings and, State of New York,have invented certain Improvements in Methods of and Means forEqualizing the Potentials of Grounding-Points, of which the following isa specification. s

In. grounded signaling circuits, as in certain classes of telegraphcircuits, the vary ing diflerences of ground potential between separatedstations may be of such. magnitude as to seriously interfere with theoperation of the system through their action in irregularly decreasingor increasing the operating currents. I p

The object of this invention is to equalize the potentials at thegrounding pomts, this being effected by applying to the round connectionat one station a potential which will tend to neutralize the groundpotential differences.

In the accompanying drawings, Figure 1 shows diagrammatically onearrangement of instrumentalities by which my invention may be carriedout; and Fig. 2 is a similar representation of a more simple system.

Similar characters of reference apply to like parts throughout thevarious figul es of the drawings.

The letters 0 O designate telegraph stations between which there areshown as extending a single transmission line L and a duplex line L thelatter including the artificial lines Z, Z All the circuits connectingthese stations may be supplied with current from batteries B, B or othersources of electrical energy. The batteries and the artificial lines areprovided at the stations with grounds G and G and it may be assumed thatthese are subjected to ground potentials of such a fluctuating characterthat G may sometimes be positive with respect to G and sometimesnegative. These grounds are joined by an equalizing conductor L which isindependent of the telegraph lines, and with said conductor at thestation 0 is associated a source of variable potential and a controllingmeans therefor. The former preferably consists of a generator D havingan armature 10, which may be in series with the conductor L, and a fieldwinding 11. For the controlling means I prefer a polar relay R, thewinding of which is in the conductor L, while itstongue is united toone-"terminal of the field winding of the generaton- The fixed contacts12 and 13 of the relay R are connected through preferably adjustableresistances .14, 14 to oppositely poled batteries B and B, the othersides of which are joined to the second terminal of the field winding. Ahighresistance 15 may be placed in parallel with the field winding toreduce sparking at the relay contacts. -At the station 0 a specialgrounding point or connection is shown at G on the opposite side of thegenerator armature from the regular grounding point G The station 0 isalso shown as provided with a ground connection in the conductor L. Thismay, however, be at any convenient point which is at substantially the ssame potential as G.

In using the herein described organization for carrying out my method,the resistances 14, 14: are so proportioned or adj ustedand thegenerator terminals and relay contacts so connected that when thecurrent in the conductor L, due to the diverse ground potentials at Gand G flows in one direction, as from G to G the consequent movement ofthe relay tongue against one contact, as 12, puts the battery B incircuit with the field winding 11 increasing the generator voltage sothat the potential at G is increased with relation to G. If, on theother hand, the ground current through con ductor L flows in theopposite direction, the relay tongue is moved against contact 13,battery B is applied to the field winding and the generator voltagealtered to decrease the potential at G with respect to G. Equalizingimpulses of the proper sign are thus rapidly applied by the generator tothe ground conductor, so that the potential at and G is at all timesapproximately the same and the current through the relay winding ismaintained close to zero. It

will be understood that whether the fluctuashort circuits the resistance17, increasin generator so that the potentia atGH'ls lncrea'sed withrelation to that at the voltage G Except as described, the adjustmentand operation of this arrangement difl'ers from th'at previouslydisclosed only in ways which will be obvious.

4 Having thus described my invention, I

claim I 1. The method of equalizing thepotentials of grounding points atseparated stations I potentials of grounding points at separatedstations which consists in connecting conducti vely grounds at suchstations, and applying tothe conductive connection at one stationpotentials opposite in sign and varying as the differences in groundpotential. 3. The'method of equalizing the potentials ofgrounding pointsatseparated stations which consists in establishing a conductiveconnection to ground between such stations. applying to said conductiveconnect1on at one station an equalizing potential with respect to theground potential at the other station, and controlling saidequalizingpotential by the current flow due to the diflference inpotentials between the grounding points. 4. The method of neutralizingpotential difierences between, the grounding points of signaling lineswhich consists in prov ding a conductive connection between the points1ndependent of the signaling lines, and applying to said conductiveconnection a neutralizing potential as great as the maximum differenceof potential between the grounding points.

V '5. A ground connection for signaling systems comprising a conductorjoining separated stations of a system, a source of electrical energyincluded in the conductor, and automatic means associated with theconductor for controlling the potential of said source.

I i so:

6. A ground connection for signaling systems comprising a conductoroining separated statlons of a system, an electric generator having anarmature and field winding,-

the armature being included in said conductor, a source of electricalenergy in circuit opposite polarity, and means associated with theconductor for joining either source to the field winding.

8. The combination with telegraph stations and a telegraph line unitingthe same, of a ground connection for the line ateach station, and meansindependent of the telegraph line for equalizing differences of groundpotential between the ground connections. v r

9. The combination with telegraph stations and a tele raph line unitingthe same. of a conductor grounded at each station and furnishing theground connection for the telegraph line at one station, an electricgenerator situated at one of the stations and having an armature andfield winding, the armature being included in the conductor, a relayhaving its winding in the conductor, and a source of electrical energyin circuit with the contacts of the relay and field winding of'thegenerator. 7

10. The combination with telegraph stations and a grounded telegraphline uniting the same, of a conductor grounded at each station andfurnishing the ground connection for the telegraph lines at onestation,- an electric generator situated at one of the stations andhaving. an armature and field winding, the armature being included inthe conductor, a polar relay having its winding in the conductor, andsources of electrical energy of opposite polarity either of which may bejoined to the field winding of the generator through the contacts of thepolar relay.

11. The combination with signaling stations and a line uniting the same,of a conductor joining the stations and to which the signaling line isconnected at each station, a source of electrical energy included in theconductor, and automatic means associated with the conductor forcontrolling the potential of said source. v

Tn testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses, this 23rd day of Witnesses:

CHAS. A. ROBINSON,

RAYI'S. HOYT.

